1. Field of the Invention
The present invention relates to novel biphenyl compounds having muscarinic receptor antagonist or anticholinergic activity. The invention also relates to pharmaceutical compositions comprising these compounds, processes and intermediates for preparing these compounds and methods of using these compounds to treat pulmonary disorders.
2. State of the Art
Pulmonary or respiratory disorders, such as chronic obstructive pulmonary disease (COPD) and asthma, afflict many millions of people worldwide and are a leading cause of morbidity and mortality. Muscarinic receptor antagonists are known to provide bronchoprotective effects and therefore are useful for treating respiratory disorders, such as COPD and asthma. Muscarinic receptor antagonists are typically administered by inhalation to treat these disorders. However, even when administered by inhalation, a significant amount of the antagonist is often absorbed into the systemic circulation resulting in systemic side effects, such as dry mouth, mydriasis and cardiovascular side effects. In addition, many inhaled muscarinic receptor antagonists have a relatively short duration of action requiring that they be administered several times per day. This multiple-daily dosing regime is inconvenient and creates a significant risk of inadequate treatment due to patient non-compliance with the required frequent dosing schedule.
Accordingly, a need exists for new muscarinic receptor antagonists, in particular, those having high potency and reduced systemic side effects when administered by inhalation. Additionally, a need exists for inhaled muscarinic receptor antagonists having a long duration of action thereby allowing for once-daily or even once-weekly dosing. Such compounds are expected to be particularly effective for treating pulmonary disorders, such as COPD and asthma, while reducing or eliminating side effects, such as dry-mouth and constipation.